The detection of changes in the circulation and surface topography of the optic nervehead and adjacent structures is crucial for the early diagnosis of glaucoma. A new technique has recently been invented (by Shapiro) to quantitate these changes. This technique, called laser contour angiography, has been used to obtain high precision topographic data in normal human subjects. The next step is to study the development of glaucoma in order to gain an understanding of the relationships between the time courses of the intraocular pressure, optic disc topography and the papillary and peripapillary circulation. Because only a small proportion of ocular hypertensive patients go on to develop visual field loss, such a study in human subjects would have to involve a large patient population and would require many years of observation. The recent availability of an animal model of chronic glaucoma, in which the ocular media usually remain clear, makes it possible to study these relationships over a short time span and under well controlled conditions. The objectives of the proposed research are to 1) acquire the necessary circulatory and topographic data by conducting a longitudinal study in monkey eyes which have been rendered glaucomatous by photocoagulation of the trabecular meshwork area of their anterior chamber angle, 2) develop a quantitative understanding of the pathogenesis of optic disc cupping by correlating the topographic and circulatory measurements with the time courses of the intraocular pressure, perfusion pressure, and histopathology, 3) develop a method for predicting damage to the optic disc which is based upon the measurements obtained, and 4) to test the predictive method by conducting a prospective study in a limited number of monkey eyes. The method for obtaining the surface topography is to use a set of laser generated stripes as the illumination in a fluorescein angiogram, and to extract the topographic information from the course of the stripes as they follow the surface.